Pet owners find that it is a nuisance to continually let a pet in and out of the house and frequently provide a door for the pet so the pet can come and go at will. Frequently such doors take the form of a series of triangular flexible members arranged to form an iris. A pet can easily push its way through the center of such an iris and it will spring back to keep out the weather.
One difficulty with such pet doors is that stray pets or other animals will frequently follow the owner's pet into the house or alternatively, come in the house at some opportune time. Accordingly, it would be highly desirable to provide a device which would allow the owner's pet to come and go but which would prevent stray pets and other animals from entering the house.
In accordance with the present invention, a very simple and inexpensive device is desired wherein the owner's pet can come and go from the house, while stray pets and other animals are kept out of the house.